Make sure that Path Finder is located in the Applications folder
(in case you are using macOS Mojave) Use System Preferences > Security & Privacy > grant Full Disk Access to Path Finder

Open your terminal and paste the following command to check if Path Finder has been slapped with the quarantined extended attribute:
xattr /Applications/"Path Finder.app"

If you see com.apple.quarantine returned as output from that last command, then go ahead and run this next command:
xattr -d com.apple.quarantine /Applications/"Path Finder.app"

You won't get any feedback or output from that command, but that's okay because you can just run the first command again to see for yourself if the com.apple.quarantine attribute shows up again. It shouldn't, and now Path Finder is freed from Apple quarantine jail. Restart your PathFinder now.

Actually PF is not crashing but encounters frequent exceptions. This happens in the middle of normal operation as when I open a new window or move a file into a folder. Still happens under 8.3.8 (1923).